Antistatic rotational molding polyolefin composition as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to an antistatic rotational molding polyolefin composition as well as a preparation method and application thereof. The antistatic rotational molding polyolefin composition is prepared by selecting specific components such as mPE resin, conductive carbon black, an antistatic agent, an antioxidant and the like through the processes of mixing, granulating, grinding and the like, and has excellent mechanical strength and relatively low surface resistivity; the method is suitable for rotational molding of military packaging box products with permanent antistatic requirements. The surface resistivity of the prepared composition can reach 108-109 omega, and the product has a good permanent antistatic effect, has excellent mechanical strength while ensuring the antistatic effect, and is suitable for rotational molding processing. The preparation method is simple in process, low in cost and easy to implement industrially.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to an antistatic roto-molded polyolefin composition and a preparation method and application thereof. Background Art

[0002] Military packaging boxes can be used for the packaging, storage and transportation of various military supplies. When used for packaging flammable and explosive items or precision instruments, there will be higher requirements for the box material. Usually the material is required to have permanent and stable antistatic properties, and the mechanical properties of the material are also required to be high.

[0003] Polyethylene material has excellent electrical insulation properties, and its surface resistivity is usually 10 15 Ω or more, static electricity is likely to accumulate during processing and use, leading to static leakage, electromagnetic interference, static dust, and electric shock or discomfort when in contact with the human body, and even static fire, explosion, or damage to precision instruments. Generally speaking, the surface resistivity of the material is 10 12 Ω and above are called insulating materials, 10 6 ~10 12 Ω is called antistatic material, and 10 6 Ω or less is a conductive material.

[0004] For polyethylene materials, conductive materials such as antistatic agents, conductive carbon black, metal microfibers and metal powders are usually added to achieve the purpose of antistatic or conductive. Traditional antistatic agents are composed of small molecule surfactants, containing hydrophilic groups and lipophilic groups. Since they are not completely compatible with resins, they constantly migrate to the surface of resin products during use. Their hydrophilic groups absorb moisture in the air, thereby dispersing static charges and reducing the surface resistivity of resin products. The antistatic agent inside the resin constantly migrates to the surface until it is completely consumed, so its effect is only effective within a certain time range (usually 1 to 3 months) and under certain conditions of use (a certain humidity).

[0005] Patent CN201510612239.9 discloses a polyethylene composite material for rotational molding that is resistant to electrical breakdown and permanent antistatic, which is made by mixing the following components in percentage by mass: 90-99.9% polyethylene powder, 0.1-10.0% metal powder. The prepared polyethylene composite material has good insulation while maintaining a permanent antistatic effect. The metal of the metal powder is selected from one metal or an alloy composed of several metals selected from silver, copper, gold, aluminum, molybdenum, magnesium, tungsten, zinc, nickel, iron, platinum, tin, and lead. This composite material is not only costly, but also complicated in process and high in density, and is not suitable for the field of military packaging boxes. Summary of the invention

[0006] In view of the deficiencies of the prior art, the object of the present invention is to provide an antistatic roto-molding polyolefin composition, which is prepared by selecting specific mPE resin, conductive carbon black, antistatic agent, and antioxidant components. The antistatic roto-molding polyolefin composition has excellent mechanical strength and low surface resistivity, has good permanent antistatic effect, and is suitable for roto-molding;

[0007] Another object of the present invention is to provide a preparation method and application of an antistatic rotomolded polyolefin composition.

[0008] The technical solution adopted by the present invention is as follows:

[0009] The antistatic roto-molded polyolefin composition is composed of the following raw materials in parts by weight:

[0010]

[0011] The mPE resin uses 1-hexene as a comonomer, has a melt mass flow rate of 4.8 to 5.7 g / 10 min, and a density of 0.932 to 0.938 g / cm 3 .

[0012] The mPE resin is analyzed by continuous self-nucleation annealing thermal fractionation method: the high temperature fraction greater than 125.3°C has a melting peak area of ​​43-49%; the low temperature fraction less than 98.3°C has a melting peak area of ​​8-12%. Preferably, mPE R335HL is purchased from Qilu Branch of Sinopec.

[0013] The antistatic agent is a polyether ester amide and polyolefin block copolymer, with a melting point of 132-137°C, a melt mass flow rate of 10-20 g / 10 min, and a density of 1.02-1.03 g / cm 3 The preferred polymer permanent antistatic agent is PELECTRON PVL, which is purchased from Sanyo Chemical Industries, Ltd. of Japan. The antistatic agent is distributed in fine layers or tendons on the surface of the product and is spherical inside, thereby leaking static charge in a "core-shell structure".

[0014] The conductive carbon black particle size is ≤40nm and the specific surface area is ≥600m 2 / g, oil absorption value ≥360mL / 100g. Preferably, superconducting carbon black CHEZACARB AC-70 is purchased from Czech Petrochemical.

[0015] The antistatic agent PELECTRON PVL and CHEZACARB AC-70 superconducting carbon black of the specific structure selected by the present invention have a synergistic effect, and the prepared composite has significantly reduced resistivity and good mechanical properties, and can meet the requirements of military packaging boxes.

[0016] The antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 1098, and antioxidant H10.

[0017] The preparation method of the antistatic roto-molded polyolefin composition comprises the following steps:

[0018] (1) Place mPE resin, antistatic agent, conductive carbon black and antioxidant in a high-speed mixer, stir at a speed of 1000 to 1500 r / min for 1 to 2 minutes, and mix them evenly;

[0019] (2) adding the uniformly mixed material obtained in step (1) into a co-rotating twin-screw extruder, melt-mixing, and extruding and granulating to obtain an antistatic rotomolded polyolefin composition.

[0020] In the step (2), the extruder temperature is 180-230°C.

[0021] The antistatic rotomolding polyolefin composition is used for preparing military packaging boxes.

[0022] The preparation method of the military packaging box comprises the following steps:

[0023] (1) Grinding: Grind the prepared antistatic roto-molded polyolefin composition into fine powder on a grinder, wherein the powder with a particle size of 40 to 100 mesh accounts for 60 to 90 wt.%, and the powder with a particle size of 40 to 80 mesh accounts for 30 to 60 wt.%.

[0024] (2) Molding: Add the ground fine powder into the mold, then move it into the heating chamber of the rotational molding machine, heat it at 240-270°C, and rotate it continuously along two mutually perpendicular axes for 20-40 minutes.

[0025] (3) Demolding: Air cool for 25 to 35 minutes, open the mold and demold.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The antistatic rotomolded polyolefin composition of the present invention has a surface resistivity of up to 10 8 ~10 9 Ω, can effectively inhibit the accumulation of static electricity, has a good antistatic effect, in addition, the antistatic effect is long-lasting and stable, will not disappear due to changes in the environment or the extension of the use time, greatly improving the service life of the rotational molding product;

[0028] (2) The antistatic roto-molding polyolefin composition of the present invention has excellent mechanical strength and is particularly suitable for roto-molding processing, which can meet the strength and toughness requirements of the product during use and improve the comprehensive performance of the product;

[0029] (3) The method for preparing the antistatic rotomolded polyolefin composition of the present invention has simple process, low cost and is easy to implement industrially. DETAILED DESCRIPTION

[0030] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0031] Unless otherwise specified, the raw materials used in the examples and comparative examples are conventional commercially available products.

[0032] Some of the raw materials used in the embodiments and comparative examples are described as follows:

[0033] mPE resin mPE R335HL, purchased from Qilu Branch of Sinopec;

[0034] Antistatic agent PELECTRON PVL, purchased from Sanyo Chemical Industries, Ltd., Japan;

[0035] Conductive carbon black CHEZACARB AC-70, purchased from Czech Petrochemical;

[0036] Roto-molding grade polyethylene resin UR644 was purchased from Lotte Chemical, South Korea;

[0037] Roto-molding grade polyethylene resin 6329U, purchased from Matrix Company, UK;

[0038] Roto-molding grade polyethylene resin LL8446, purchased from ExxonMobil Corporation, USA;

[0039] Conductive carbon black N220 was purchased from Cabot Corporation, USA.

[0040] The raw material compositions of the rotomoulding compositions of Examples 1 to 4 and Comparative Examples 1 to 5 are shown in Tables 1 to 2, in terms of weight fractions.

[0041] Table 1 Examples 1 to 4 Raw material composition

[0042] project Example 1 Example 2 Example 3 Example 4 mPE R335HL 100 100 100 100 CHEZACARB AC-70 2 2 3 3 PELECTRON PVL 8 10 8 10 Antioxidant 1010 0.6 0.6 0.6 0.6 Antioxidant 168 0.3 0.3 0.3 0.3

[0043] Table 2 Comparative Examples 1 to 5 Raw Materials Composition

[0044]

[0045]

[0046] Example 1

[0047] The antistatic roto-molded polyolefin composition is composed of the following raw materials in parts by weight:

[0048]

[0049] The preparation method of the antistatic roto-molded polyolefin composition comprises the following steps:

[0050] (1) mPE R335HL, PELECTRON PVL, CHEZACARB AC-70, antioxidant 1010 and antioxidant 168 were placed in a high-speed mixer and stirred at a speed of 1500 r / min for 2 min to mix evenly;

[0051] (2) adding the uniformly mixed material obtained in step (1) into a co-rotating twin-screw extruder, melt-mixing, and extruding granulation, wherein the temperatures of each section of the extruder are 190° C., 210° C., 210° C., 220° C., 230° C., and 230° C. in sequence, to obtain an antistatic rotomolded polyolefin composition.

[0052] Example 2

[0053] The antistatic roto-molded polyolefin composition is composed of the following raw materials in parts by weight:

[0054]

[0055] The preparation method of the antistatic roto-molded polyolefin composition has the same steps as Example 1.

[0056] Example 3

[0057] The antistatic roto-molded polyolefin composition is composed of the following raw materials in parts by weight:

[0058]

[0059] The preparation method of the antistatic roto-molded polyolefin composition has the same steps as Example 1.

[0060] Example 4

[0061] The antistatic roto-molded polyolefin composition is composed of the following raw materials in parts by weight:

[0062]

[0063] The preparation method of the antistatic roto-molded polyolefin composition has the same steps as Example 1.

[0064] Comparative Example 1

[0065] The difference between Comparative Example 1 and Example 1 is that the conductive carbon black CHEZACARB AC-70 is replaced by an equal amount of conductive carbon black N220.

[0066] The rotomolding composition is composed of the following raw materials in parts by weight:

[0067]

[0068] The preparation method of the rotomolding composition has the same steps as Example 1.

[0069] Comparative Example 2

[0070] The difference between Comparative Example 2 and Example 2 is that the antistatic agent PELECTRON PVL is replaced by an equal amount of antistatic agent hydroxyethyl alkylamine.

[0071] The rotomolding composition is composed of the following raw materials in parts by weight:

[0072]

[0073]

[0074] The preparation method of the rotomolding composition has the same steps as Example 1.

[0075] Comparative Example 3

[0076] The difference between Comparative Example 3 and Example 4 is that an equal amount of rotomolding grade polyethylene resin UR644 is used to replace mPER335HL.

[0077] The rotomolding composition is composed of the following raw materials in parts by weight:

[0078]

[0079] The preparation method of the rotomolding composition has the same steps as Example 1.

[0080] Comparative Example 4

[0081] The difference between Comparative Example 4 and Example 4 is that an equal amount of rotomolding grade polyethylene resin 6329U is used to replace mPER335HL.

[0082] The rotomolding composition is composed of the following raw materials in parts by weight:

[0083]

[0084] The preparation method of the rotomolding composition has the same steps as Example 1.

[0085] Comparative Example 5

[0086] The difference between Comparative Example 5 and Example 4 is that an equal amount of rotomolding grade polyethylene resin LL8446 is used to replace mPER335HL.

[0087] The rotomolding composition is composed of the following raw materials in parts by weight:

[0088]

[0089]

[0090] The preparation method of the rotomolding composition has the same steps as Example 1.

[0091] The performance testing methods of the rotomolding compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 5 of the present invention are as follows:

[0092] (1) Compression molding specimen preparation process: In accordance with the requirements of GB / T 1845.2-2021, an overflow mold is used for compression molding. The compression molding process is shown in Table 3.

[0093] Table 3 Compression molding process conditions

[0094]

[0095] (2) Standard environment for specimen conditioning and testing: in accordance with the provisions of GB / T 2918-2018, the temperature is (23±2)°C, the relative humidity is 45% to 55%, and the specimen conditioning time is 24 h.

[0096] (3) Melt flow rate (MFR): tested in accordance with GB / T 3682.1-2018, with a test temperature of 190°C.

[0097] (4) Density: Tested in accordance with GB / T 1033.2-2010.

[0098] (5) Tensile yield stress: tested in accordance with GB / T 1040.2-2022, type I spline, tensile speed 50 mm / min.

[0099] (6) Nominal strain at break: tested according to GB / T 1040.2-2022, type I spline, tensile speed 50 mm / min.

[0100] (7) Simply supported beam notched impact strength: tested in accordance with GB / T 1043.1-2008.

[0101] (8) Flexural modulus: tested in accordance with GB / T 9341-2008.

[0102] (9) Surface resistivity: Tested in accordance with GB / T 1410-2006.

[0103] The performance test results of the rotomolding compositions prepared in Examples 1 to 4 of the present invention and Comparative Examples 1 to 5 are shown in Tables 4 and 5:

[0104] Table 4 Performance evaluation of Examples 1 to 4

[0105]

[0106] Table 5 Performance evaluation of comparative examples 1 to 5

[0107]

[0108]

[0109] It can be seen from Tables 4 to 5 that the difference between Comparative Example 1 and Example 1 is that the conductive carbon black CHEZACARB AC-70 is replaced by an equal amount of conductive carbon black N220, and its surface resistivity is significantly improved, and other mechanical properties are basically equivalent; the difference between Comparative Example 2 and Example 2 is that the antistatic agent PELECTRON PVL is replaced by an equal amount of antistatic agent hydroxyethyl alkylamine, and its surface resistivity is significantly improved, and other mechanical properties are basically equivalent; the difference between Comparative Examples 3, 4, and 5 and Example 4 is that mPE R335HL is replaced by other types of roto-molding grade polyethylene resins, and its surface resistivity is slightly improved. Among them, the formula with UR644 and LL8446 as the base resin has a significant decrease in the simply supported beam notched impact strength. Although the formula with 6329U as the base resin has a better simply supported beam notched impact strength, the melt mass flow rate is too low and it is difficult to roto-mold.

Claims

1. An antistatic rotomolded polyolefin composition, characterized in that: It is composed of the following raw materials in parts by weight:

2. The antistatic rotomolding polyolefin composition according to claim 1, characterized in that The mPE resin uses 1-hexene as a comonomer, has a melt mass flow rate of 4.8 to 5.7 g / 10 min, and a density of 0.932 to 0.938 g / cm 3 .

3. The antistatic rotomolding polyolefin composition according to claim 1, characterized in that: The mPE resin is analyzed by continuous self-nucleation annealing thermal classification method: the high temperature fraction above 125.3°C has a melting peak area of ​​43-49%; the low temperature fraction below 98.3°C has a melting peak area of ​​8-12%.

4. The antistatic rotomolding polyolefin composition according to claim 1, characterized in that: The antistatic agent is a polyether ester amide and polyolefin block copolymer, with a melting point of 132-137°C, a melt mass flow rate of 10-20 g / 10 min, and a density of 1.02-1.03 g / cm 3 .

5. The antistatic rotomolding polyolefin composition according to claim 1, characterized in that: The conductive carbon black particle size is ≤40nm and the specific surface area is ≥600m 2 / g, oil absorption value ≥360mL / 100g.

6. The antistatic rotomolding polyolefin composition according to claim 1, characterized in that: The antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 1098, and antioxidant H10.

7. A method for preparing the antistatic rotomolded polyolefin composition according to any one of claims 1 to 6, characterized in that: Here are the steps: (1) mPE resin, antistatic agent, conductive carbon black and antioxidant are placed in a blender and mixed evenly; (2) adding the uniformly mixed material obtained in step (1) into a co-rotating twin-screw extruder, melt-mixing, and extruding and granulating to obtain an antistatic rotomolded polyolefin composition.

8. The method for preparing the antistatic rotomolded polyolefin composition according to claim 7, characterized in that: In the step (2), the extruder temperature is 180-230°C.

9. Use of the antistatic rotomolding polyolefin composition according to any one of claims 1 to 6, characterized in that: Used in the preparation of military packaging boxes.

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